Welcome aboard Tiene! I just joined recently having become aware of my E3/4 status, and have learned a ton (kilo LOL) from this wonderful group of people on this forum.
I was a bit skeptical at 1st re trying to avoid what I thought was a predisposed genetic freight train coming my way, but I have now come around to believing diet/lifestyle CAN make a preventative, non-pharma intervention impact on this disease.
Re the Spain/healthy analog, my parents were both southern European immigrants until their early 20's, and I know for CERTAIN they ate a very strong mediterranean diet prior to coming to North America. My mom and dad, now 75, have AD and PD, respectively (noting the majority of their lives lived in Canada). Although they continued to eat a relatively strong mediterranean diet (I grew up with it), of course there were Western digressions, but I would say mainly towards excessive caloric intake (carbs, red meats, dairy, some processed foods) given the bounty of North America. My mom in middle age, also lived a relatively sedentary and non-social lifestyle (again, bad hallmarks for AD), whereas my dad, who was a house painter, was exposed to CONSTANT toxicity present in the old oil based toxic paints of the 60's/70's/80's (I could not stomach an open can, and he inhaled it 8 hrs/day), which many now believe are strong risk factors for PD (again, environmental impact).
I think this forum is a very positive energy, and a wake up call to take proactive control our destiny.